Technical Field
Embodiments of the invention relate generally to medical devices and, more specifically, to a system and method of potential equalization monitoring for medical devices.
Discussion of Art
During a medical procedure, any number of electrical medical devices may be connected to a patient at any given time throughout the duration of the procedure, as well as connected to one another through the patient. For example, common pieces of equipment often used during medical procedures may include an ECG monitor, an electrocautery device and a catheter having an ablation electrode connected to a radiofrequency energy source.
When attaching an electrical device to a patient, it is desirable that the devices, as well as the patient, are “floating” from a grounding standpoint (i.e., ungrounded) to prevent shocking or burning the patient during a surgery or other medical procedure. In particular, if all the devices and the patient are not floating, stray electrical currents from defective devices and the like may pass through the patient and dissipate through various pathways to the ground (e.g., through the ECG grounding lead, the operating room table and/or a physicians body, causing electrical shock. However, even when all the electrical devices within an operating room and the patient are floating, they may not all be “floating” to the same degree. Accordingly, there may exist a difference in electrical potential between the various devices and/or one or more of the devices and the patient, which can be a source of undesirable noise.
This difference in electrical potential between the various devices is typically resolved by connecting each electrical device to a common AC power source and connecting equipotential grounding lugs on the rear of each device to a common ground, sometimes referred to as a star point.
Throughout a procedure, with the addition and subtraction of devices, the equipotential ground current within the system may vary. If one device is grounded except at the dedicated common source, the grounding system forms a loop path through which current may flow. At times, excess charge may be introduced to the patient. This change in the balance of charge can lead to increased noise and other adverse effects, such as reduction in the amplifier dynamic range. As will be readily appreciated, noise may also effect the visibility and clarity of the electrogram. While existing systems are sufficient to mitigate the risk of shocking or burning a patient, such systems are simply not capable of determining the cause of the change in the balance of charge (i.e., the source of electrical charge), or where and how current is flowing between the various devices and the patient, making it difficult for a physician to diagnose and resolve noise issues within the system.
In view of the above, there is a need for a potential equalization monitoring system that is capable of diagnosing the source of increased isopotentials at a patient.